一种基于宽带激励的虚拟时间反转方法  

Virtual time reversal method based on broadband excitation

作　　者：蔡建[1,2] 石立华[2] 袁慎芳[1] 邵志学[2] 

机构地区：[1]南京航空航天大学航空宇航学院,南京210016 [2]解放军理工大学工程兵工程学院,南京210007

出　　处：《仪器仪表学报》2011年第1期218-224,共7页Chinese Journal of Scientific Instrument

基　　金：国家自然科学基金(10872217);国家自然科学基金重点项目(50830201);国家高技术研究发展计划(863)(2007AA03Z117);航空科学基金(20090852015)资助

摘　　要：针对主动Lamb波监测中常见的低信噪比问题和传统时间反转方法降低监测信号空间分辨率的不足,提出一种采用宽带激励求取损伤散射路径传递函数的虚拟时间反转方法并应用于复杂结构的多损伤成像中。理论研究并经实验验证表明该方法不但能够有效实现Lamb波多损伤散射信号在相应损伤处聚焦增强,抑制了边界反射信号和噪声,提高了信噪比,而且与传统时间反转方法相比,提高了损伤聚焦波包的空间分辨率,增强了对于多个损伤的监测能力。最后的成像结果显示虚拟时间反转方法能够改善复杂板结构中两个近邻损伤的成像质量。Aiming at the shortcoming of low signal to noise rate（SNR） of diagnostic signals in active Lamb wave monitoring and the problem that traditional time reversal method deteriorates the spatial resolution of Lamb waves,a virtual time reversal（VTR） method is presented and applied to multi-damage imaging in a complicated structure in this paper,which adopts broadband excitation to acquire transfer functions of damage scattered path.Both theoretical analysis and experimental results indicate that,using the VTR method,multi-damage scattered signals can be successfully focused and enhanced on the corresponding defects,and moreover boundary reflections and noises are inhibited.The SNR of the scattered signals is then improved.Furthermore,compared with conventional time reversal method,the spatial resolution of focalized damage scattered wave-packets is improved,which helps to strengthen the ability of Lamb waves for monitoring multiple damages.Final imaging results show that the image quality of the dual adjacent damages in a complicated plate structure can be enhanced using the proposed VTR method.

关 键 词：结构健康监测 时间反转 LAMB波 宽带激励 多损伤监测 损伤成像 

分 类 号：TP18[自动化与计算机技术—控制理论与控制工程] TN911.7[自动化与计算机技术—控制科学与工程]